1. Field of the Invention
The present invention relates to a reflection type liquid crystal display apparatus for displaying an image, a character, and the like using a liquid crystal, a substrate used for the reflection type liquid crystal display apparatus, a liquid crystal projector apparatus using the reflection type liquid crystal display apparatus, and a rear projection apparatus.
2. Description of the Related Art
In the reflection type liquid crystal display apparatus, a majority of lights incident from a transparent substrate side and transmitting a liquid crystal layer is reflected by a pixel electrode (reflection electrode) having a reflection characteristic. However, a part of the light transmitting the liquid crystal layer enters a gap between the reflection electrodes. The light entering a gap between the reflection electrodes propagates an interlayer film (usually a dielectric substance such as SiO2 and the like) between wirings and reaches a ground silicon substrate at a probability, while reflecting between the electrodes and attenuating or transmitting the metal electrode which is the wiring and attenuating. The carrier generated by that light changes a storage voltage of the reflection electrode. This phenomenon is referred to as a light leakage.
In the case of positive and negative field inversion operations (with respect to a reference voltage, voltages negative and positive and equal in absolute value are written every one time by a double-speed operation, respectively), when the light leakage exceeds a reference, the change in the storage voltage by the light leakage is always in the same direction, and therefore, the positive and negative field voltages are prevented from substantially becoming the same absolute value. Hence, a flicker (a difference of brightness between the positive and negative fields) arises. Phenomenally, by measuring this flicker, the degree of the light leakage can be estimated.
With respect to the light leakage, by controlling a quantity of the light reaching the silicon substrate, the change in the storage voltage of the reflection electrode can be substantially suppressed. One of the methods for controlling the quantity of the light reaching the silicon substrate includes one for attenuating the light directly coming from the gap between the reflection electrodes by providing a light shielding layer directly under the reflection electrodes. Further, there is a method in which the interlayer film, through which the light between the light shielding layer and the reflection electrode propagates, is made thin to make a light propagating path thin, thereby suppressing the quantity of the light propagating through the interlayer film. Further, there is a method in which an anti reflection film is formed at the interlayer film side of the upper and lower electrodes of the interlayer film in which the light propagates, thereby attenuating the quantity of the light.
Japanese Patent Application Laid-Open No. 2002-221717 discloses that the distance between the reflection electrode and the light shielding layer is made small to suppress the light leakage.
Japanese Patent Application Laid-Open No. 2004-004337 discloses a double structure made of the light shielding layer and the anti reflection film, and a structure having no anti reflection film in the gap between the reflection electrodes.
Japanese Patent Application Laid-Open No. 2005-326615 discloses a structure in which the light shielding layer is of two layers, and the upper layer thereof is connected to the reflection electrode, and does not exist in the gap between the reflection electrodes, and the underlying oblique layer is not connected to the reflection electrode, and is made flat.
The present inventor has found that, when a distance between the reflection electrode and the light shielding layer is made small to suppress the light leakage, a problem arises that there is an interference between the light reflected by the light shielding layer and going out from the gap between the reflection electrodes and the light reflected by the reflection electrode.
An object of the present invention is to suppress the light leakage and to provide a substrate for a reflection type liquid crystal display apparatus that reduces the effect of interference, a reflection type liquid crystal display apparatus using the same, and a liquid crystal projector apparatus.